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Give the subsequent History of the Gametocytes (the Sexual 

 Generation). 



In Plasmodium falciparum the crescentic gametocytes 

 become rounded and free from the remains of their con- 

 taining blood corpuscles. They undergo maturation in 

 the stomach of the mosquito. In the male or micro- 

 gainetocyte the nucleus breaks up, and its chromatin sub- 

 stance passes into four or six slender processes, like flagella, 

 which grow out from the body and are detached as active 

 microgametes (" sperms "). 



The female or macrogametocyte, after extruding a portion 

 of the nucleus at the surface, becomes a macrogamete 

 (" ovum ") ready for fertilisation. Conjugation takes 

 place ; the minute active microgamete enters the larger 

 macrogamete and loses its thread-like form. The two 

 nuclei fuse, and the result is a zygote that elongates into 

 an ookinete, which bores its way through to the outside 

 of the stomach and there encysts (an oocyst or spore-cyst) 



Describe the further Development of the Oocyst. 



4, Segmentation of the nucleus and protoplasm results 

 in a number of irregular- shaped sporo blasts. In each 

 sporoblast the nucleus divides up into numerous small 

 nuclei which pass to the periphery. Then a number of 

 slender processes grow out from the surface of the sporo- 

 blast and each contains one of the little nuclei. Thus, by 

 sporogony, a great number of minute sporozoites are formed 

 which soon go free from the residual protoplasm. There 

 may be hundreds or even as many as ten thousand of these 

 motile germs within the cyst. In one instance a mosquito 

 was found with more than 500 cysts on the outside of its 

 stomach. 



How do the Sporozoites get into the Proboscis of the Mos- 

 quito ? 



When the cysts burst they are free in the hsemoccale or 

 body cavity. They travel to the salivary glands ; and 

 when the mosquito " bites," they pass in swarms into 

 the proboscis along with the saliva. 



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